Ive heard and seen some images and videos of soliders building their own antidrone ammo. They rip the tip off the casing and heat shrink a coulple of bbs together and crimp them to the casing. I’m not certain how legitimate or effective it is but I’ve seen several videos and images of it. They recomend staggering the homemade rounds with tracer rounds to help with aiming.
Guns should never be cleaned with live ammo inside them.